Telephone-exchange system.



F. R. Mommy. TELEPHONE .EXCHANGE SYSTEM APPLICATION FILED AUG.21.1918.

Pata-amai; q

. R. MGBERTY.

NE. EXUHANGE SYSTEM.

APLGATION FILED AUG. 21. 1913.

Patented Jan. 5, 1915.

3 SBEBTS*SHEET 3.

UNTED STATES ATENT QlilllCE,

FRANK ROBERT MCBERTY, 0F ANTWERP, BELGIUM, ASSIGNOR '.Ov WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

TELEPHONE-EXCHANGE SYSTEM.

i Application filed August 2l,

To all zr/Lom, 'it may concern Be it known that I, FRANK Ronnn'rv Md BLRTY7 a citizen of the United States, residing at i9 Boulevard Leopold, Antwerp, Belgium, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise7 and exact description.

This invention relates to telephone er:- change systcmsand has to do more particu-A larly with a test or controlling circuit for telephone exchange systems utilizing automatic switches to extend the desired con nection.

In automatic switches of the character referred to there is usually a circuit known as the test circuit thereof including a test brush on the movable portion of such switch which tests on the one hand thc calling or norrcalling condition of the line, or, on the other hand, the busy or idle condition of the line, depending upon whether such auto matic switch is a line finder switclu a trunk finder switch or a selector. rhe invention herein described has particularly to do with an improved system and arrangement involving such a test circuit.

In British Patent No. 21,960/11 is shown a line finder of the character referred to, and in British` Patent No. 21,259/11 is shown a trunk finder switch and a selector of the lclnu'acter referred to. .Vhile the invention 'is disclosed and described herein with specilic reference to switches of the character referred to, it will, of course, be understood it is not limited to switches or' these sp Y types` nor to any speci c types of switches, but is readily applicablej as will be understood by those skilled in the art, to switcnes and systems lwidely varying in typ and character.

One of the features of the invention'i's a test circuit in which two test relays associated with the test circuit, performing in teroi'ierating but independenti'unctions, a included in such circuit in parallel hereby a more sensitive and accurate operation of such` relays is acceinililished.

A/inother 'feature oi the invention r particularly to autonialic switches are powaer driven and in which test is placed upon the' line selected innnel that the brushes ot the switch come in tact with the terminals of such liuc, though the motion of the switch is not en Specification or Letters Patent.

Patented Jan. 5, 1915.

reis. Serial No. 785cm.

rested until such brushes are properly ccntcred upon such terminals. This feature involves an arrangement of the circuit of the power-control test relay hy which the povrci tor driving` the brush carriage of the switr-lris maintained and cut ol'r' at the proper time7 in such a manner that this relay operates to cut oill such power by the closure oi: the circuit therethrough rather than hy the removal of a shunt from around such relay.

fr still further feature of the invention pertains to the reducion of current fiuctua tions in the test circuit of the selector switches oi the character above referred to.

`Further novel and improved features of the invention will sutiicicnily appear in the detailed description hereinafter set Jforth.

In the draw-'ings z-l i gares l and l show the invention as applied to a line finder switch of the type set Yforth in British Patent HQ/ll; Fig. a diagrammatic detail ci a portion of the apparatus and circuits of Fig. i; and Fig'. El shows the invention as applied to a selector switch of the type shown in British Patent No. 21,259/11.

The structure of the switches themselves and of the sequence switches shown as a part of the diagrams herein will sul'liciently appear from an examination of the British patents referred to and British Patents No. 20,S-/lO--09 and No. 16567-41, and ZOll--O rfhe arrangement and ope-ration of the test circuit involving the invention will best appear in the description of the operation ot the respective switches with which it is shown herein associated.

Referrinff first to Figs. l and lL--wheii the subscriiier at sub-station 50 removes his receiver from its hook, line relay 51 is enero-ized, placing a selectable potential upon all the. nuiltiple test terminals G8 of the multiple sets of terminals 65, 66, 67, GS, individual to this subscribers line in all the liney linde-r switches serving the group to which this line belongs, and the pilot relay', enhr the atti-acti n of e line relay starts in mot-ien all such line ,.v'L, 'n mi switches u i i ieee line ent llo.

c i nte switches dny from those shown in c ranged'that he lever 6.9 will rest upon a tooth of the interrupter plate l'Oonly when .the brushes "il, "Q, 73, 74 are properly centered upon tl,y terminals, 66, 67,'68 corresponding to lsuch tooth upon plate'70. At all times when the brushes 71, 72, 73, 74 are passing from one set of terminals to the next the lever (Si) will be passing between teethon the intcrrupter plate and out of contact therewith. This is clearly shown in the drawings and especially so in Fig. 2 thereof.

In the movement of the line linder switch 75, the test brush 74 as it passes over the test terminals G8 of non-calling;r lines, will find no or insuflicieut potential existingthereon and no connections of the line finder apparatus will take place. As soon, however, as the test `brush T4 comes incontact with the terminal 68 ot a calling` line on which there exists selectable potential a circuit will be established, including with the battery, the pilot relay the armature and front contact of the line relay 51, resistance/5 3, terminal GS, brush 74. sequence s'witcli contact 59 bottom, upperhigh resistance winding);y

of the test relay T6, sequence switch contact G0 to ground and back t0 battery. this time the test brush `'Hf of no othen'line linder rests upon the terminal 68 of this call ing line., sullicient current will .pass through the upper windingof the relay '5G to energize this relay, which will thereupon attract its armature and immediately close a low resistance circuit from the brush'Yl to ground through its lower low resistance winding, which. circuit while maintaining relay 76 energized will so reduce thc potential upon the testl terminal 68 that the corrcspondimg relay 76 of another switch whose test brush 74 comes in contact with the terminal 68 of this line will not receive sullicient current for its energization and conse ucntly the switch will continue in motion. llt this time, however, the movement of thebrush carriage of the line finder T5 will not be immediately arcsted but will continue until the lever 69 o." the interruptor device, comes in contact with a toothl on the plate T0.which tooth corresponds to the desired set of terminals.

t this timea circuit will be established for the relay T7 in parallel with the low resistance winding of the relay TG, such circuit including the armature of such relay 7G,

.contact 57 bottom, relay 77, Contact 58 botstopped with the brushes in proper position over the line terminals; this relay also closes a circuit for the sequence switch 79, driving it out of its hrst and into its fourth positlon.

If at.

ltest relay Tl'is produced by the closure of the battery circuit therethrough, andthere-l fore responds quickly'rather than more sluggishly as in a circuit wherein tl1e-` operatien 1t will he.

of this relay takes place by the removal-of i a shunt therearound. Furthermore, it will be observed that t/he current liuctuations'fin the test circuit erein disclosed are much less than in the test/circuit of the character referred tol Thisiwill be apparent whenit is considered that in such test circuits suii-.`

cient current must flow from the shunt'to ground through the. interrupter device to energize the relay similar to relay' 7l' .when the shunt is removed. Therefore. when the test brush first comes in Contact with the test i terminal and the double wound test relayr 76 1 is energized, considerable current will iiow from the 'lowreslstance winding ther of to ground, whereas when ,the brushes are propee s orly centered and the shunt is remored there s being a greater resistance in the test circuit, less current flows therein although the re`` sistance must be sulliciently low to allow suflicieut current to passito energize the rela?v A TT and' to reduce the potential upon the mu tiple test terminals to such a point that ne other line finder may seize the line to which auch test terminal is individual Accordingr to the circuit of the present invention. the windings ofthe test relays 76 and 77 will be of considerably .less re sistance than the corresponding relays in test circuits of the character referred to, while maintaining the proper margins and accurateness of operation. By this means and byv-the multiple arrangement instead of the series arrangement` ot thetfest relays T6 and 77, undesirable fluctuations of cur rent will not take place in the test circuit.

Referring now more specifically to Fig.v A, l

3 itl will be observed that in the eighth po-k sitionof the sequence switch 395 the. ronp selector 300 is searchingand testing or an idle trunk line in-the selected group. s the test brush 303 movesover the termin,

lic

nuls 303 of busy lilies it'will nd insuf-Q fcient potential thereon to cause 'the 'enen' im j gization of the relay 93 by means of its hi gh resistance lefty hand. winding. when, however, the test brush 363' reaches the test terminal of an idle line upon which exists unshunted potential, siulleient eurrent will pass through the high resistance winding of the relay 93 to cause it to bef energized, thereby attractingits armaturei which will establish a parallel path through its low resistance right hand winding, so reducing the potential on the multiple test terminals 303 ot the seized line that it will test busy to all other group select-ors in which it appears. rthe interruptor lever 99 not as ret. having come in contact with the tooth of the interrupter plate 9S corresponding to thel ser` of terminals 301, B09, 3023, the relay 90 is not as jy'et en reized and the brush carriage of the group selector continues in motion until the interrupter lever comes into Contact 'ith the tooth of the i11- terrupter plate and the circuit is closedv hereihrough to ene Uize the relarv 9() which i lie cucz:

tions may take nl asdescrxlied in 'the british izitent 54o. 214.252) referred to.

2.5 neioiinig specifically to lug. 2,-fth1s ole rlv shows the relative arrangethu contact brush 7l and the inver iii) to 'the contact terminal pending tooth upon ;tlie Se interi plate T0. This ligure also shows diegrr inatically the circuits associated with suol: parts.

seen tli `t as soon as the test brush l comes in Contact riti the test terminal the. 35 test relug.' is energized closmgithrtuigh its sev-ond winding a. lou' resistance .busy guard for the test terminal 68, and, at the saine t.; e preparing u circuitfor the powereontrol test reloj: which circuit will he :it Closed u moment later when the lerer 69 z with the tooth of' the inter- Tl) corresponding to the termif line seizeo; and the relay 77 Will n open the citt-uit oli the driving t so and close the circuit of the holda Si. which arrests the. ,movement -li u ith the brushes properly cendesired terminals.

'nirticulorly described and nature of the said invention nanner saine is to be per- .eclare that what l clai1nis:-

ephone exchange system, the rfi h apliiralitiv ot lines. of 5111-. l Q i'or intelconnectingr the pr-.rallel adapted to reester is idle, und means ajv' to render the inul- -lr line busy and means to arrest. the moveone exchange u a' plurality o ln this ligure it will be Asaid selectors having normali up toniatic selectors adapted to interconnect the suine. a cirvuit useaociated with a h oi" said selectors adapted to test said lines and in- Hurling two relays, one responiliu' innuedi ateljv it thil line is idle to rtuiltl` busy its ,multiplo terminals and preparing a circuit in parallel with i :Ultl l'or lie 'infiel' relay which controlsv the stopping oil the selector, und .i su itt-h nfrriwl by the select-or for closing suial circuit to Stop the same when the selector is' properly positioned.

3. ln u telephone exchange system, the combination with a 'pluralitr ot lines7 olf uutoiuatic selectors adapted to in ercon f' il saule, u constantly rotating' h lt atlag' f' hc-.Coupleil toI Suhl :analogous to ilrivo th suine, a circuit assoeiuled 'li nach of said selectors. adapted to tet f ,lul lines and ini'l uling; two relays vin parallel adapted to re- .siimul it' the lineI tested idle, one lo render its multiple terminals busy and the oil ,r to uncouple the selector from the power shaft.

l. lu a telephone exchange system. the combination with a plurality ol' lines7 ot autoinutic selectors ufflaoted to interconnect the 9^ same, a conlstanth rotating shaft adapted to loe coupled to said selectors to drire the sario, a circuit associated with each of said selectors adapted to said lines ai l in cluding tu o relays iu parallel. one irfpondy: ing iuimedi'atelv it' the line is idle to under busy its multiple terminals and preparing a circuit in parallel with itself for the other olaf. which controls the coupling olf the se lector to the shalt.y and a Switch carried by roll' 'with a. illuralit)v o'i liu. :I tors adapted to interconnect 'the power shalt For din finirr said salento tory, multiple test contacts for s to' the full potential of Sain cuit associated with each o" adapted to test said lines ani relays. one haring a high rf. tial reducingvinding. id l ingliy its high r i we u'iui'lin is idley to rend .said line liuSjf the potential ol: its iuulti,. including low resistance cuit with said battery, and pr paring a :ircuitflior 'the other relai. which controls the disconnection o'f the, power sliuft. and a suit l .l selector adapted to close. sait. circuit to stop the saine when the selector is properly positioned. l

6. In a telephone exchange stem. the combination with a plura-ilit)v of lines, o" an automatic switch for interconnecting the saine. a test circuit associated with4 switch and including tivo device-s in paralgnu lel responsive to line conditions, means con- En witness Wb ere E, I hereunto subscribe -tro11ef1 by one device to establish a busy my name This 24th yialy of July A. D., 1913.

condition at the terminals of the line tested, FRANK ROBERT MCBERTY. and means controlled by the other device to Witnesses:

5 govern the movement of the automatc F. T. `WOODWARD,

switch. HENRY W. DIEDERICB 

